Harmonic generator



HARMONIC GENERATOR Filed June 1, 1951 PHASEZ E2 I E Mae/2&7:

Patented Aug. 11, 1 953 UNITED STATES PATENT OFFICE HARMONIC GENERATOR Harold Tornheim, Chicago, 111.

Application June 1, 1951, Serial N 0. 229,467

11 Claims. 1

This invention relates to electromagnetic apparatus and is specifically directed to the provision of an electromagnetic harmonic generator or frequency multiplier capable of producing one or more designated harmonics from a given fundamental frequency.

Broadly stated, the general aims of the invention are to provide a harmonic generator having performance characteristics considerably exceeding any type of harmonic generator or frequency multiplier heretofore developed, and to accomplish this general aim with a comparatively simple and inexpensive apparatus, whereby the practical fields of usefulness of apparatus of this general character may be greatly expanded.

A further general aim of the invention is to provide means for producing an alternating electrical current wherein the apparatus may be so constructed as to arbitrarily produce an output characterized by any desired specific form of wave shape, either with or without a change of the fundamental frequency.

In pursuance of the general aims enumerated above, it is a specific object of the invention to provide a mechanism capable of producing any desired harmonic or multiple of a given fundamental frequenc and to effect arbitrary control of the wave shape of the output thereof, yet to accomplish these results with a comparatively simple electromagnetic apparatus which need include only a single output winding; and wherein this winding may be of entirely conventional conformation, comprising a cylindrical coil of multiple circular turns in a plurality of layers and adapted to be produced on conventional types of coil winding machines. This is of considerable advantage in the practical manufacture of equipment of this kind, in that it avoids the necessity of employing windings of the unusual, intricate and complex designs such as have been proposed in certain prior art devices, yet are entirely impractical to produce. Obviously, the accomplishment of this object achieves a great simplification of the apparatus employed in frequency changing equipment, and is an important factor in provision of an apparatus which may be manufactured at a reasonable cost.

A still further object of the invention is the provision of apparatus for generating harmonic frequencies and producing wave forms of specific characteristics wherein the output signal may be developed in a single output winding without resort to transformerschoke coils or other auxiliary equip A still further object of the invention is the provision of a harmonic generator having a simplified coil design, together with a magnetic circuit of unique construction, such that the characteristics of the magnetic circuit may be altered at will to produce any required frequency multiplication and wherein the magnetic circuit is so constructed as to be readily set to produce variations in amplitude of the output at any portion of the wave cycle, thus permitting arbitrary control of the shape of the output wave without variaion or modification of the output coil in which said wave is induced.

In accomplishing the foregoing objects, the present applicant has taken direct departure from the theories of operation of such types of frequency multiplying apparatus as are known to have been disclosed in the prior patented art, and has developed what is believed to be an en tirely new method of generating harmonics or multiples of a given fundamental frequency. In the practice of this method the applicant has succeeded in inducing a wanted harmonic directly into a pickup coil of perfectly conventional spool wound design. This is accomplished, according to the present invention, by providing said coil with a magnetic circuit having radial magnetic members arranged according to the specific harmonic desired, and by then subjecting the coil to the effects of a stationary radial magnetic field, and simultaneously superimposing thereon a rotating magnetic field having its lines of force extending transversely across the coil, so that the coil and its magnetic circuit are excited by the combined effects of the two fields having differing characteristics. By this method it has been found feasible to develop a rotating flux pattern in the radial magnetic members adjacent the pickup coil, so that the direction of flux in the several radial members changes in one member at a time and in predetermined succession in accordance with the fundamental frequency by which the apparatus is excited.

The present preferred apparatus for practicing this method of harmonic generation is illustrated in the drawings of this specification, wherein:

Figure 1 is a plan view of a harmonic generator pickup unit as contemplated by the present invention;

Figure 2 is a transverse sectional view of said unit, the view being taken substantially on the plane of the line 22 of Figure 1;

Figure 3 is a schematic diagram of the pickup unit and a typical polyphase exciting winding,

3 which may be energized by a fundamental frequency to provide a rotating magnetic field around the pickup unit;

Figures 4, 5, 6 and 7 are diagrammatic illustrations of the magnetic fields developed by the different portions of the apparatus of this invention:

In these, Figure 4 represents a rotating transverse magnetic field, as developed by the exciting windings pr the unit; a v

Figure 5 depicts a stationary radial field, as developed by the magnetic generator of the pickup unit;

Figure 6 shows the rotating magnetic pattern which results from superimposing the rotating transverse field illustrated in Figure 4 611 the stationary radial held of Figures; and

Figure '7 is a diagrammatic representation of the magnetic flux existing in the radial inagnetic members of the pickup unit at a given instant of time, 'it'being understood-that this flux pattern is also rotating in accordance with the rotation of the transverse magnetic field illustrated in Figure 4.

The preferred form of harmonic pickup unit illustrated '-herein consists of a pair of pickup coils or output windings, a magnetic circuit common to both output windings, anda magnetic generator which, as shown, consists-of an electromagnetic winding. 7

The magnetic circuit, generally designated as C, consists pfaninside magnetic core it, an outer magnetic shell II, and aplurality of spacedapart, radially :extendingmagnetic members R interconnecting the'opposite-ends-of the shell and the core. v I y In the'specific form of the invention illus trated, the, magnet c; core 1 0 consists of a tubular soft iron sleeve, and the outermagnetic shell ll comprises "asimilar-soft iron sleeve of con" siderably greaterdiameter than the sleeve ill, but of lesser length. They-sleeves ill and Ii are concentrically disposed and spaced apart from each'j'other, with the j shell sleeve ll intermediatelydismsedbetween the ends'of the core sleeve iflfas-shown in', Figure 2. The magnetic genera'tor of '-the unit, that is, the electromagnetic bias coil B, is disposed between the core ill and itsshe'll ll.

The opposite-endsof the core sleeve it and the'- shell';sleeye ii are interconnected by the radially extending magnetic members R which comprise opposed and alternately positionedsets of "preformed, soft iron wires oj two principal types indicated'as Ri andRZ. The innermost ends of each of these -members are secured to the ends of the core-sleeveii'l at E3, and the outer ends thereof ;are similarly secured to the shell sleeve Il-at i l. The set of wires Bleach have an outwardly, offset portion 55 and an inner vertical portionltv extending downwardly to a point adjacent the bias winding 13, and a straight, radial portion 'l'l extending thence outwardly, with'its' outer "end secured-directly to the end surfaceofthe shell sleeve-ll at Hi as aforesaid. The'm'agnetic members R2 are similarly secured to the core sleeve and the outer shell,:but-a-re formed of somewhat different configuration "so that the"straight-radial portion l8 extends directly outwardly from the fastening point l3, with the wires*behtdownwardly to form a vertical portion l9' e'xt'ending'to the fastening: point l4.

In the" assembly of the device, the'set of wires Rl' are first's ec1ired,"and theoutput. coil- 0 is placed in position before the wires R2 are mounted. Thus, when the wires R2 are placed in position and secured, the output winding 0 is disposed between the members RI which form an inside set of radial magnetic members and the alternately positioned members R2 which form a corresponding outside set.

It should be noted at this point that the output coil may be a preformed, cylindrical electromagnetic coil "of entirely conventional constructionfoo'neiSting of multiple'coaxial "circular turns of an electrical conductor in plural layers; in

short, the usual spool type Winding, which may easily 'be produced on conventional coil winding machines.

In the preferred construction illustrated, the radial magnetic member R! and R2 are uni- 'formly spaces. about the axis A of the unit, but it is th be understood that this arrangement may be varied as desired, either to compensate foranylackof unii ormity in the -magnetic field employed in the unit,-or -;-or -purposes-of accomplishinga specific "function; such as the development of an output having specific characteristics of wave shape, for example.

It is also within the contemplation of the .present invention toprovide one -or-more additional output windings. If desired, additional-windings having precisely the same'characteristics asthe winding 0 may be employed, with magnetic circuits designed to produce different harmonics thus make possible the production of an output of complex wave form representing :the resultant of -more "than one harmonic-frequency. As illustrated, however, the other --output winding is formed of two coil sections indicated --at OAand OE, respectively,-so that it may-be used with radially extending magnetic members R3 and Fa l formed --in precisely the same -manner as the members Rl =and -R2-, yet wherein --one or more ofthese members may bereplaced by a member such-astheW-ire R5 soiormed as to have a vertical portion ililextendingthrough the windingbetweenthe two sections thereo'f so that the portionOAof the wnding-Willbe within this portion of "themagnetic circuit, but the portion OB will not. This willeifect a sharp reduction of amplitude ofthe output signal at a 'fixedpoin't in the wave curveand. permitarbitrary adjustment of the magnetic circuit to vary the wave shape of theoutput at will.

It-is, of course,--also within the purview .of the inventionto effect further" variations in' -the wave shape-ofthe output by increasing-the'fiuxat any point across 'the -outputwinding by enlarging the cross sectional area of one or more of the magneticmembers; or by decreasing'the flux by reducing the cross sectional 'area. -Similarly, arbitrary control of the wave shape of the output oftheunit'may be-accomplished'by varying the spacing of the radial magnetic members, 'as required.

Operation Inoperation,- the*piclup unit disclosed hereinis energized primarily by an 'ex'ternal rotating transverse magnetic field,"'with the pickup unit disposed in coaxial -relation' with the center --of rotation of themagnetic field andwith thewindings of '-its"coils in-theplane of rotation thereof, so-thatthe straight radial. portions of the magnetic members R are disposed radially ofthe center- 0f 'said field. The magnetic'field'employed -by thepresent invention may be produced mechanically, if'desired-although it more conveniently developed by placing "thepickup 'u'ri'it as here disclosed within windings such as conventionally employed in a polyphase induction motor. Any suitable polyphase windings may be employed for this purpose, although for purposes of illustration, an exciting winding comprising two sections El and E2 has been illustrated in Figure 3 of the drawings. It has been found convenient to energize these windings from a single phase power supply by employing suitable phase splitting networks, as well understood in the electrical arts.

The function of the polyphase winding is to produce a rotating magnetic field having transverse lines of force as diagrammatically illustrated in Figure 4, but revolving at the fundamental frequency of the power supply. In such a field, the flux at any given instant is represented by the arrows TF, but it should be understood that the direction of flux across the field is never static and that the entire field pattern is rotating on the axis A in accordance with the fundamental frequency supplied to the polyphase windings. Thus the entire field may be assumed to be rotating in a clockwise direction as indicated by the arrow D.

The pickup unit itself produces a second magnetic field having flux characteristics diagrammatically illustrated in Figure 5. To this end the pickup unit includes a magnetic generator. In some applications this generator may comprise a permanent magnet, but in the form of the invention illustrated an electromagnetic bias winding B is disposed between the tubular core sleeve l0 and the outer shell sleeve I l of the unit. When this winding is energized, a stationary field with radial lines of force will be produced. This field may be represented by the arrows RF diverging from the axis A of Figure 5.

It is to be recalled, however, that the pickup unit is disposed in coaxial relation with the rotating magnetic field of Figure 4, so that the two magnetic fields are superimposed upon each other. The resultant magnetic field is illustrated in Figure 6 wherein it will be seen that at a given instant of time corresponding to the point of rotation shown in Figure 4, the greatest flux density will be across the field in the direction of the arrow F, with the lines of force on either side thereof curving outwardly in generally radial arrangement, as illustrated by the arrows Fl, F2, F3, F4, and F5. In considering this pattern, however, it should also be borne in mind that the entire pattern is continuously rotating about the center A in the direction D and at a rate in accordance with the fundamental frequency as supplied to the exciting winding.

This rotating magnetic pattern is employed in the present invention to impart magnetic energy to the radially extending magnetic members R of the pickup unit, as diagrammatically shown in Figure 7. As the field revolves, the radial wires R will saturate under the influence of the rotating magnetic pattern, but it will be observed from Figures 6 and '7 that there will be one point on the circumference of the field at which the magnetic flux will be changing, and

will momentarily act in a reverse direction as indicated by the arrow CF in Figure '7. However, since the pattern is rotating as indicated by the arrow D, this reversal of flux in the radial wires will take place in sequential order around the entire group of radial members, and at a rate in synchronism with the rotation of the magnetic pattern therearound.

From the foregoing, it should be apparent that when the unit is in operation the radially extending magnetic members are saturated with flux according to a pattern which is the resultant of the radial and rotating fields employed herein, and that the movement of this pattern will be effective to cause periodic and successive reversal of the flux around the entire group of radia1 members, in accordance with the fundamental frequency supplied to the equipment. Thus, the flux in the radial members extending across the pickup windings and disposed on the opposite sides thereof will, in turn, induce harmonic frequencies into the pickup windings, and the output frequency will be directly dependent on the number and arrangement of the radially extending magnetic members. It follows that by the provision of the required number of radial members, any desired harmonic of the fundamental frequency may be generated, and it is also within the purview of the invention to vary the spacing, shape or cross section of the magnetic members and make such adjustments of the relative magnetic density of the radial and rotating magnetic fields as may be required to produce outputs having wave forms of any de sired amplitude or wave shape, as well as to develop multiples of the input frequency.

It is also to be observed that this result is accomplished by a relatively simple electromagnetic device having no moving parts whatsoever, and so designed that, if desired, several separate and independent pickup units may be mounted within the same rotating magnetic field and employed to operate in synchronism with each other. Moreover, it will be seen that the teachings of the present invention accomplish the production of multiple frequencies, harmonics and specific wave shapes without the need of auxiliary transformers and by the employment of a single output winding in an environment wherein the winding may be constructed to have a relatively large number of turns and to thus develop a considerable output potential, so that it is practicable in use without requiring unnecessarily precise instruments or excessive amplification. Moreover, these advantageous results are accomplished by a mechanism which is comparatively simple to manufacture and so designed as to require only the conventional type of cylindrical spool type winding, so that the accomplishment of the result does not depend on the employment of basket weave coils, toroidal windings or other unconventional types of windings which are extremely difiicult and expensive to manufacture and which ordinarly cannot be standardized to give the uniformity of performance required in present day electrical equipment.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent is:

1. In a harmonic generator, in combination, a polyphase electromagnetic winding for producing a rotating transverse magnetic field and a harmonic pickup unit including a magnetic circuit having an internal magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the core sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit comprising a cylindrical electromagnetic bias coil disposed around said core' and within said shell and consisting of multiple coaxial circular turns of an electrical conductor, said windingbeing adapted when en-- ergized to develop a magnetic field extending radially between said core and its surrounding shell; together with an output winding comprise ing a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed 'extcriorly of the internal magnetic core of the device and in a position generally parallel to and coaxial with the bias winding thereof; and a plurality of radial magnetic members extending inwardly across the turns of the output coil from the outer tubular magnetic shell to the magnetic core of the unit and spaced apart from each other; said magnetic members comprising two complementary sets of iron wires secured in alternate relationship to the outer magnetic shell and extending radially inwardly therefrom with their inner ends secured to the core in alternating circular relationship, but with the alternate sets of said wires having radially extending portions thereof alternately disposed on opposite sides 'of said output winding.

-2. a harmonic generator, in combination, 'a polyphase electromagnetic winding -for producing a rotating transverse magnetic field and a harmonic pick-up unit including a magnetic circuit having an inter-rial magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the core sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit comprising a cylindrical electromagnetic bias coil disposed around core and Within said shell and consisting of multiple coaxial circular turns of an electrical conductor, being adapted when energized to develop a niag-netic field extending radially between said core and its surrounding shell; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial --circular turns of an electrical conductor disposed exteriorly of the internal magnetic core of the device and in position generally parallel to and coaxial with the bias winding thereoi; and a plurality of radial magnetic members extending inwardly across the turns of the output coil from the outer tubular magnetic shell to the magnetic core of the unit and spaced apart from each other.

-3. -I-n a harmonic generator, in combination, a polyph-ase electromagnetic winding for producing a rotating trans-verse cnag-netic field and a harmonic pickup unit including magnetic circuit "raving an internal magnetic core consisting of a tubular iron sleeve, with aneXter-nal magne'tic shell consisting of a tubular iron sleeve shorter than thc -oore sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit adapted when energized to develop a magnetic field extending radially oetween said core and its surrounding shell; together with an output winding comprising a cylindricalelectromagnetic coilconsisting of-multiple coaxial'circular turns of an electrical conductor disposed exteriorly of the internal magnetic'core ofthedevice; anda plurality of-radial magnetic members-extending inwardly across the turns of theoutput coil :from the-outer tubular magnetic sh'ell 'to tlfe-ma'gnetic core'of the unit and "spaced "apart i'ro'm each other; said -magnetic members comprising "two complementary sets of iron wires secured in alternate relationship to the outer magnetic shell'and' each I extending 'radially inwardly therefrom with their :inner ends secured "to the-core in alternating circular relationship, but with the alternate sets of said wires having radially extending portions thereof alternately disposed on opposite sides of said output winding.

4. In a harmonic generator, in combination, a polyphase electromagnetic winding for producing a rotating transverse magnetic field and a harmonic pickup unit including a magnetic circuit having an internal magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the core sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit adapted when energized to develop a magnetic held extending radially between said core and its surrounding shell; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed eXte-ri-ori of the internal magnetic core of the device; and a plurality of radial magnetic members extending inwardly across the turns of no output coil from the outer tubular magnetic shell to the magnetic core of the unit and spaced apart from each other.

5. A harmonic pick-up un it including a magnetic circuit having an internal magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the coresleeve hut concentric therewith and radially spaced therefrom; a mag netic generator in said pickup unit comprising a cylindrical electrorn'agn c bias coil disposed around said core and w hin said shell and consistin of multiple coama'l circular turns of an electrical conductor, said wmdirrg being "adapted when energized to develop a magnetic field ex tending radially between said "core and its surrounding shell; together with an output winding comprising a cylindrical electromagnetic "coil consisting of multiple coaxial -ci-rcu1ar turns of an electrical conductor disposed -'ex'terior-ly or the internal magnetic 'core'o'f the device and ina position generally parallel to and coaxial with the bias winding thereof; and a plurality of radial magnetic members extending inw-arclly "across the turns of the output 'co'il from the "outer i'iubi-ilar magnetic shell to the magnetic core of the unit and spaced apart from each other said magnetic members comprising two complementary sets "of iron wires secured in alternate relationship to theou'ter magnetic s'he'll'and each extending radiailly inwardly therefrom with :their inner ends secured to the "core in alternating circular *rlationship, but with the alternate sets of said wires having radially extending portions thereof altern'ately disposed on opposite sides 0'2 said output winding.

6. Afha'rmonic pickup uni-t including a magnetic -'circuit having an "internal magnetic core consistingof a tubular iron sleeve, with an exterrfal magnetic shell-consisting 'of-a tubular ir'on sleeve "shorter than the core sleeve but concentrio the'rewith and radially spaced therefrom; a magnetic generator :in said pickup unit '-'co1npnising a cylindrical electromagnetic bias [coil fdiS posed around :said 'core and within said shell and consisting 10f multiple coaxial circular iturns 20f an "electrical conductor, said winding being adapted when energized to develop .a magnetic fieldzexten'ding radially between lsaidlcore (and its surroundingshell; together withlan-output winding comprising a cylindrical electromagnetic .coil consisting of multiple coaxial circular turns -of an electricalconductordisposedexteriorlyof Lthe internal magnetic core of the device and in a position generally parallel to and coaxial with the bias winding thereof; and a lurality of radial magnetic members extending inwardly across the turns of the output coil from the outer tubular magnetic shell to the magnetic core of the unit and spaced apart from each other.

7. A harmonic pickup unit including a magnetic circuit having an internal magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the core sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit adapted when energized to develop a magnetic field extending radially between said core and its surrounding shell; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed exteriorly of the internal magnetic core of the device; and a plurality of radial magnetic members extending inwardly across the turns of the output coil from the outer tubular magnetic shell to the magnetic core of the unit and spaced apart from each other; said magnetic members comprising two complementary sets of iron wires secured in alternate relationship to the outer magnetic shell and each extending radially inwardly therefrom with their inner ends secured to the core in alternatingcircular relationship, but with the alternate sets of said wires having radially extending portions thereof alternately disposed on opposite sides of said output winding.

8. A harmonic pickup unit including a magnetic circuit having an internal magnetic core consisting of a tubular iron sleeve, with an external magnetic shell consisting of a tubular iron sleeve shorter than the core sleeve but concentric therewith and radially spaced therefrom; a magnetic generator in said pickup unit adapted when energized to develop a magnetic field extending radially between said core and its surrounding shell; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed exteriorly of the internal magnetic core of the device; and a plurality of radial magnetic members extending inwardly across the turns of the output coil from the outer vtubular magnetic shell to the magnetic core of .the unit and spaced apart from each other.

9. In a harmonic generator, the combination, with means for producing a rotating transverse magnetic field, of a harmonic pickup unit 1n- =cluding internal and external magnetic members with an electromagnetic bias coil between said members and adapted when energized to develop a stationary magnetic field extending radially therefrom; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed in a position generally parallel to and coaxial with the bias winding thereof; and a plurality of radial magnetic members spaced apart from each other and extending inwardly across the turns of the output coil; said magnetic members comprising two complementary sets secured in alternate relationship and having radially extending portions thereof alternately disposed on opposite sides of said output winding.

10. In a harmonic generator, the combination, with means for producing a rotating transverse magnetic field, of a harmonic pickup unit including internal and external magnetic members with an electromagnetic bias coil between said members and adapted when energized to develop a stationary magnetic field extending radially therefrom; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed in a position generally parallel to and coaxial with the bias winding thereof; and a plurality of radial magnetic members spaced apart from each other and extending inwardly across the turns of the output coil.

11. A harmonic pickup unit including internal and external magnetic members with an electromagnetic bias coil between said members and adapted when energized to develop a stationary magnetic field extending radially therefrom; together with an output winding comprising a cylindrical electromagnetic coil consisting of multiple coaxial circular turns of an electrical conductor disposed in a position generally parallel to and coaxial with the bias winding thereof; and a plurality of radial magnetic members spaced apart from each other and extending inwardly across the turns of the output coil; said magnetic members comprising two complementary sets secured in alternate relationship and having radially extending portions thereof alternately disposed on opposite sides of said output winding.

HAROLD TORNHEIM.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 410,468 Thomson Sept. 3, 1889 432,050 Kammeyer July 15, 1890 1,559,295 Stoller Oct. 27, 1925 

